Staking assembly, staking assembly manufacturing method, hub unit bearing, hub unit bearing manufacturing method, automobile, and automobile manufacturing method

ABSTRACT

Axial relative movement of an auxiliary member ( 30 ) and a hub body ( 22   z ) is performed, the hub body ( 22   z ) and an inner race ( 21 ) are combined with each other in an axial direction, and a part of the hub body ( 22   z ) deformed by a blade ( 33 ) of the auxiliary member ( 30 ) is disposed inside an engagement concave portion ( 26 ) of the inner race ( 21 ).

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a National Stage of International Application No.PCT/JP2020/004339 filed Feb. 5, 2020, claiming priority based onJapanese Patent Application No. 2019-018459, filed Feb. 5, 2019, thecontents of which are incorporated herein by reference.

TECHNICAL FIELD

The present invention relates to a staking assembly, a staking assemblymanufacturing method, a hub unit bearing, a hub unit bearingmanufacturing method, an automobile including a hub unit bearing, and anautomobile manufacturing method.

BACKGROUND ART

A vehicle wheel and a braking rotation body of an automobile aresupported by a hub unit bearing to be rotatable with respect to asuspension device. FIG. 13 shows a structure of a hub unit bearing 1described in U.S. Pat. No. 5,226,738. The hub unit bearing 100 has aconfiguration in which a hub 102 is rotatably supported on an innerradial side of an outer race 101 through a plurality of rolling elements103. The outer race 101 includes a double row of outer race tracks 104 aand 104 b provided in an inner peripheral surface and a stationaryflange 105 provided in an axially intermediate portion to support andfix the outer race 101 to a knuckle of the suspension device. The hub102 includes a double row of inner race tracks 106 a and 106 b in anouter peripheral surface and includes a rotational flange 107 providedin an axial outer portion protruding outward in the axial direction inrelation to the axial outer end surface of the outer race 101. Theplurality of rolling elements 103 are arranged for each row between thedouble row of the outer race tracks 104 a and 104 b and the double rowof the inner race tracks 106 a and 106 b in a rolling manner. With sucha configuration, the hub 102 is rotatably supported on the inner radialside of the outer race 101.

Additionally, the “outside” in the axial direction means the left sideof FIG. 13 which is the outside of the vehicle body in a state in whichthe hub unit bearing 1 is assembled to the automobile. In contrast, the“inside” in the axial direction means the right side of FIG. 13 which isthe center side of the vehicle body in a state in which the hub unitbearing 1 is assembled to the automobile.

In the example shown in the drawings, the hub 102 is a combination of ahub body 108 and an inner race 109. The hub body 108 includes the innerrace track 106 a on the outside of the axial direction in the double rowof the inner race tracks 106 a and 106 b in the outer peripheral surfaceof the axially intermediate portion and includes the rotational flange107 in the axial outer portion. Further, the hub body 108 includes afitting cylinder portion 110 having an outer diameter smaller than thatof a portion adjacent to the outside of the axial direction in the axialinner portion existing on the inside of the axial direction in relationto the inner race track 106 a on the outside of the axial direction.

The inner race 109 includes the inner race track 106 b on the inside ofthe axial direction in the double row of the inner race tracks 106 a and106 b in the outer peripheral surface. Such an inner race 109 isexternally fitted to the fitting cylinder portion 110 while the axialouter end surface abuts against a step surface 111 existing in the axialouter end portion of the outer peripheral surface of the fittingcylinder portion 110. In this state, the axial inner end surface of theinner race 109 is held down by a staking portion 112 formed byplastically deforming a cylindrical portion extending in the axialdirection from the axial inner end portion of the fitting cylinderportion 110 outward in the radial direction. With such a configuration,the separation of the inner race 109 with respect to the hub body 108 isprevented.

In the structure described in U.S. Pat. No. 5,226,738, if a force inwhich the staking portion 112 holds down the axial inner end surface ofthe inner race 109 is not sufficient, there is a possibility thatrelative slippage (displacement, creep) occurs between the hub body 108and the inner race 109.

European Patent Application, Publication No. 0927651 describes atechnique of preventing creep between the hub body and the inner race byroughening the surface roughness of a chamfered portion connecting theaxial inner end surface and the inner peripheral surface of the innerrace. Further, U.S. Pat. No. 5,822,860 describes a structure in which achamfering dimension of a chamfered portion connecting the axial innerend surface and the inner peripheral surface of the inner race changesin the circumferential direction.

CITATION LIST Patent Literature [Patent Literature 1]

-   U.S. Pat. No. 5,226,738

[Patent Literature 2]

-   European Patent Application, Publication No. 0927651

[Patent Literature 3]

-   U.S. Pat. No. 5,822,860

SUMMARY OF INVENTION Technical Problem

However, even in the structure described in European Patent Application,Publication No. 0927651, if a force in which the staking portion holdsdown the axial inner end surface of the inner race is not sufficient,there is a possibility that creep occurs between the hub body and theinner race. Particularly, in the case of the structure in which a gapexists between the chamfered portion of the inner race and the stakingportion, it is not possible to obtain the creep prevention effect due tothe roughening of the surface roughness of the chamfered portion.

In the structure described in U.S. Pat. No. 5,822,860, a force in whichthe staking portion holds down the axial inner end surface of the innerrace becomes uneven in the circumferential direction. Accordingly, thereis a possibility that the inner race may be distorted unevenly in thecircumferential direction and the roundness of the inner race track maydecrease. As a result, the bearing performance of the hub unit bearingmay deteriorate.

An object of the present invention is to realize a staking assemblycapable of preventing displacement between a first member and a secondmember and a structure of a hub unit bearing capable of reliablypreventing creep from occurring between a hub body and an inner race.

Solution to Problem

According to an aspect of the present invention, there is provided amethod of manufacturing a staking assembly including: preparing a firstmember, a second member including an engagement concave portion and ahole allowing the first member to be inserted thereinto, and anauxiliary member including a blade; combining the first member and thesecond member with each other in an axial direction; moving theauxiliary member and the first member relatively in an axial directionso that a part of the first member deformed by the blade of theauxiliary member in the axial relative movement is disposed inside theengagement concave portion of the second member; and forming a stakingportion with respect to the second member in the first member.

According to an aspect of the present invention, there is provided amethod of manufacturing a staking assembly including: preparing a firstmember, a second member including a concave portion and a hole allowingthe first member to be inserted thereinto, and an auxiliary member;moving the auxiliary member and the first member relatively in an axialdirection and including (a) combining the first member with the secondmember in the axial direction in accordance with the axial relativemovement and (b) forming a convex portion engaging with the concaveportion in accordance with the axial relative movement in the firstmember by the auxiliary member; and forming a staking portion withrespect to the second member in the first member.

According to an aspect of the present invention, there is provided astaking assembly including: a first member; and a second memberincluding a hole allowing the first member to be inserted thereinto andcombined with the first member, wherein the second member includes aconcave portion, and wherein the first member includes a staking portionwith respect to the second member, a convex portion provided in an outersurface of the first member and engaging with the concave portion of thesecond member, and a groove provided in the outer surface of the firstmember and extending from the convex portion toward a front end of thestaking portion.

According to an aspect of the present invention, there is provided astaking assembly including: a first member; and a second memberincluding a hole allowing the first member to be inserted thereinto andcombined with the first member, wherein the second member includes aconcave portion, wherein the first member includes a staking portionwith respect to the second member and a convex portion provided in anouter surface of the first member and engaging with the concave portionof the second member, wherein the concave portion of the second memberincludes a first surface intersecting an axial direction of the firstmember, wherein the convex portion of the first member includes a secondsurface parallel to the first surface of the concave portion, andwherein the first surface and the second surface are in close contactwith each other in the axial direction.

According to an aspect of the present invention, there is provided a hubunit bearing including: an outer race including an outer race track; ahub including an inner race track; and a plurality of rolling elementsarranged between the outer race track and the inner race track, whereinthe hub includes a hub body including an outer surface and an inner racedisposed on the outer surface of the hub body and held by the hub body,wherein the inner race includes a concave portion, and wherein the hubbody includes a staking portion with respect to the inner race, a convexportion provided in the outer surface of the hub body and engaging withthe concave portion of the inner race, and a groove provided in theouter surface of the hub body and extending from the convex portiontoward a front end of the staking portion.

According to an aspect of the present invention, there is provided amethod of manufacturing a hub unit bearing, wherein the hub unit bearingincludes an outer race including an outer race track, a hub including aninner race track, and a plurality of rolling elements arranged betweenthe outer race track and the inner race track and wherein the hubincludes a hub body including an outer surface and an inner racedisposed on the outer surface of the hub body and held by the hub body.The method includes: preparing the inner race including an engagementconcave portion and an auxiliary member including a blade; combining thehub body and the inner race with each other in an axial direction;moving the auxiliary member and the hub body relatively in the axialdirection so that a part of the hub body deformed by the blade in theaxial relative movement is disposed inside the engagement concaveportion of the inner race; and forming a staking portion with respect tothe inner race in the hub body.

According to an aspect of the present invention, there is provided a hubunit bearing including: an outer race including a double row of outerrace tracks provided in an inner peripheral surface; a hub including adouble row of inner race tracks provided in an outer peripheral surface;and a plurality of rolling elements which are arranged for each rowbetween the double row of the outer race tracks and the double row ofthe inner race tracks in a rolling manner. The hub includes an innerrace and a hub body. The inner race includes an inner race track on theinside of an axial direction in the double row of the inner race trackson the outer peripheral surface. The hub body includes an inner racetrack which is formed in an outer peripheral surface of an axiallyintermediate portion directly or through another member and is locatedon the outside of the axial direction in the double row of the innerrace tracks, a fitting cylinder portion which exists on the inside ofthe axial direction in relation to the inner race track on the outsideof the axial direction and to which the inner race is externally fitted,and a staking portion which is bent outward in a radial direction froman axial inner end portion of the fitting cylinder portion and holdsdown an axial inner end surface of the inner race. The inner raceincludes an engagement concave portion provided at one or a plurality ofpositions in a circumferential direction to open to the axial inner endsurface and the inner peripheral surface. The hub body includes anengagement convex portion provided at one or a plurality of positions inthe circumferential direction to engage with the engagement concaveportion.

The hub body can further include a concave groove which is recessedinward in the axial direction and extends outward in the radialdirection from a portion which is close to the outside of the engagementconvex portion in the radial direction and in which a phase in thecircumferential direction coincides with that of the engagement convexportion in an axial outer surface of the staking portion.

According to an aspect of the present invention, in order to manufacturethe above-described hub unit bearing, there is provided a method ofmanufacturing the hub unit bearing including: press-fitting the innerrace into the fitting cylinder portion of the hub body before formingthe staking portion; allowing the engagement convex portion to engagewith the engagement concave portion of the inner race while forming theengagement convex portion and the concave groove by pressing one or aplurality of positions in the circumferential direction of an outerperipheral surface of a radial outer portion of the cylindrical portion,extending inward in an axial direction from the fitting cylinder portionof the hub body before forming the staking portion, outward in the axialdirection to be plastically deformed; and coupling and fixing the innerrace and the hub body by plastically deforming the cylindrical portionoutward in a radial direction to form the staking portion.

It is preferable to perform the press-fitting and the engaging at thesame time. In this case, the inner race can be press-fitted into thefitting cylinder portion of the hub body before forming the stakingportion by pressing the inner race, externally fitted to an axial innerend portion of the hub body before forming the staking portion, outwardin the axial direction by a portion deviating from a protrusion portionin a pressing punch including the protrusion portion protruding inwardin the radial direction at one or a plurality of positions of the innerperipheral surface in the circumferential direction and the engagementconvex portion can be allowed to engage with the engagement concaveportion of the inner race while forming the engagement convex portion bypressing one or a plurality of positions in the circumferentialdirection of the radial outer portion of the cylindrical portion outwardin the axial direction to be plastically deformed by the protrusionportion.

Further, since the pressing punch includes a pressing surface on a frontend surface, a gap can exist between a front end surface of theprotrusion portion and a bottom surface of the engagement concaveportion while the pressing surface comes into contact with a portiondeviating from the engagement concave portion in an axial inner endsurface of the inner race when performing the press-fitting and theengaging at the same time.

It is preferable to further include confirming whether or not theengagement convex portion engages with the engagement concave portionafter the engaging. It is possible to perform an operation of confirmingwhether or not the engagement convex portion engages with the engagementconcave portion by, for example, with naked eyes or diagnosing imagesphotographed by a camera.

An automobile according to an aspect of the present invention includesthe staking assembly or the hub unit bearing.

In an automobile manufacturing method according to an aspect of thepresent invention, the hub unit bearing is manufactured by the hub unitbearing manufacturing method of the present invention.

Advantageous Effects of Invention

According to the aspect of the present invention, for example, since theengagement convex portion of the hub body engages with the engagementconcave portion of the inner race, it is possible to reliably preventcreep from occurring between the hub body and the inner race. Further,it is possible to prevent the staking assembly from being displacedbetween the first member and the second member.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a cross-sectional view showing a hub unit bearing according toan embodiment of the present invention.

FIG. 2 is a cross-sectional view showing a state seen from the left sideof FIG. 1 when a braking rotation body and a stud are omitted.

FIG. 3 is a view corresponding to a cross-section X-X of FIG. 2 , whichshows a state before an axial outer end portion of an inner race isexternally fitted to an axial inner end portion of a hub body beforeforming a staking portion and an axial inner end surface of the innerrace is pressed by a pressing punch.

FIG. 4 is a view corresponding to a cross-section of X-X of FIG. 2 ,which shows a state in which the pressing punch is displaced downwardfrom the state shown in FIG. 3 and a front end surface of the pressingpunch comes into contact with the axial inner end surface of the innerrace.

FIG. 5 is an enlarged view of a Y part of FIG. 4 .

FIG. 6 is a view corresponding to a cross-section X-X of FIG. 2 , whichshows a state in which the pressing punch is further displaced downwardfrom the state shown in FIG. 4 so that a press-fitting step and anengaging step are performed at the same time.

FIG. 7 is an enlarged view of a Z part of FIG. 6 .

FIG. 8 is a view corresponding to a cross-section X-X of FIG. 2 , whichshows a state after the press-fitting step and the engaging step arecompleted.

FIG. 9 is a perspective view showing a state in which the press-fittingstep and the engaging step are completed when viewed from the inside ofthe axial direction.

FIG. 10 is a view corresponding to a cross-section X-X of FIG. 2 , whichshows a state in which a hub is taken out.

FIG. 11(a) to FIG. 11(d) are schematic horizontal cross-sectional viewsshowing an engagement concave portion of an inner race and an engagementconvex portion of a hub body.

FIG. 12 is a partial schematic view of a vehicle including a hub unitbearing (bearing unit).

FIG. 13 is a cross-sectional view showing an example of a conventionalstructure of a hub unit bearing.

DESCRIPTION OF EMBODIMENTS

FIGS. 1 to 10 show an embodiment of the present invention. In theexample of the drawings, a hub unit bearing 1 has a configuration inwhich a hub 3 is rotatably supported on the inner radial side of anouter race 2 through a plurality of rolling elements 4 a and 4 b. Thehub unit 1 includes the outer race 2 which has outer race tracks 5 a and5 b, the hub (staking assembly) 3 which has inner race tracks 11 a and11 b, and a plurality of rolling elements 4 a and 4 b which are disposedbetween the outer race tracks 5 a and 5 b and the inner race tracks 7 aand 7 b.

The outer race 2 includes a double row of the outer race tracks 5 a and5 b and a stationary flange 6. In an example, the outer race 2 is madeof hard metal such as medium carbon steel. In another example, the outerrace 2 can be made of another material. The double row of the outer racetracks 5 a and 5 b are respectively formed in the inner peripheralsurfaces of the axially intermediate portions of the outer race 2. Theouter race tracks 5 a and 5 b have a partially conical concave surfaceinclined in a direction in which the diameter increases toward adirection away from each other in the axial direction. The stationaryflange 6 is formed in the axially intermediate portion of the outer race2 to protrude outward in the radial direction. The stationary flange 6includes a support hole 7 which is a screw hole provided at a pluralityof positions of the radially intermediate portion in the circumferentialdirection. The outer race 2 is supported and fixed to a knuckle 8 insuch a manner that a bolt 10 inserted through a passage hole 9 formed inthe knuckle 8 constituting a suspension device is screwed into thesupport hole 7 of the stationary flange 6 from the inside of the axialdirection and is further tightened.

The hub (staking assembly, staking unit) 3 is disposed on the innerradial side of the outer race 2 to be coaxial with the outer race 2. Thehub 3 includes a double row of the inner race tracks 11 a and 11 b and arotational flange 12. The double row of the inner race tracks 11 a and11 b are formed in a portion facing the double row of the outer racetracks 5 a and 5 b in the outer peripheral surface (outer surface) ofthe hub 3. The double row of the inner race tracks 11 a and 11 b have apartially conical convex surface inclined in a direction in which thediameter increases toward a direction away from each other in the axialdirection. The rotational flange 12 is formed in a portion located onthe outside of the axial outer end portion of the outer race 2 in theaxial direction of the hub 3 to protrude outward in the radialdirection. The rotational flange 12 includes an attachment hole 13 whichis provided at a plurality of positions of the radially intermediateportion in the circumferential direction to penetrate in the axialdirection. In the example of the drawings, a serration portion formednear a base end of a stud 15 is press-fitted into the attachment hole 13in order to couple and fix a braking rotation body 14 such as a disc ora drum to the rotational flange 12. Further, an intermediate portion ofthe stud 15 is press-fitted into a passage hole 16 formed in the brakingrotation body. Furthermore, a nut 19 is screwed into a male screwportion formed at a front end portion of the stud 15 and is furthertightened while the male screw portion is inserted through a passagehole 18 formed in a wheel 17 in order to fix the wheel 17 constituting avehicle wheel to the rotational flange 12.

Additionally, the “outside” in the axial direction means the left sideof FIG. 1 and the lower side of FIGS. 3 to 10 corresponding to theoutside of the vehicle body while the hub unit bearing 1 is assembled tothe automobile. In contrast, the “inside” in the axial direction meansthe right side of FIG. 1 and the upper side of FIGS. 3 to 10corresponding to the center side of the vehicle body while the hub unitbearing 1 is assembled to the automobile. Further, the attachment hole13 is not shown in FIGS. 3, 4, 6, 8, and 10 .

Each of the rolling elements 4 a and 4 b is disposed at a plurality ofpositions between the double row of the outer race tracks 5 a and 5 band the double row of the inner race tracks 11 a and 11 b in a rollingmanner while being held by cages 20 a and 20 b. In an example, each ofthe rolling elements 4 a and 4 b is made of hard metal such as bearingsteel or ceramics. In another example, the rolling elements 4 a and 4 bcan be made of another material. With such a configuration, the hub 3 isrotatably supported on the inner radial side of the outer race 2.Further, in the example of FIG. 1 , tapered rollers whose outer diametergradually increases from one end to the other end in the axial directionare used as the rolling elements 4 a and 4 b.

The hub (staking assembly) 3 is substantially a combination of an innerrace (second member) 21 and a hub body (first member) 22. The hub 3includes a hub body 22 having an outer peripheral surface (outersurface) 23 a and an inner race 21 disposed on the outer peripheralsurface (outer surface) 23 a of the hub body 22 and held by the hub body22.

The inner race 21 includes the inner race track 11 b on the inside ofthe axial direction on the outer peripheral surface in the double row ofthe inner race tracks 11 a and 11 b. In an example, the inner race 21 ismade of hard metal such as bearing steel. In another example, the innerrace 21 can be made of another material.

The hub body 22 includes the inner race track 11 a on the outside of theaxial direction on the outer peripheral surface of the axiallyintermediate portion in the double row of the inner race tracks 11 a and11 b. Further, the hub body 22 includes the rotational flange 12 whichis provided in the outer portion in the axial direction and exists onthe outside of the axial direction in relation to the inner race track11 a on the outside of the axial direction. In an example, the hub body22 is made of hard metal such as medium carbon steel. In anotherexample, the hub body 22 can be made of another material. Further, thehub body 22 includes a fitting cylinder portion (cylinder portion) 23which is provided in the axial inner portion existing on the inside ofthe axial direction in relation to the inner race track 11 a on theoutside of the axial direction so that an outer diameter is smaller thanthat of a portion near the outside of the axial direction and the innerrace 21 is externally fitted thereto. Furthermore, the hub body 22includes a staking portion (swage portion, crimp portion) 24 which isbent outward in the radial direction from the axial inner end portion ofthe fitting cylinder portion 23 and holds down an axial inner endsurface 34 of the inner race 21. For example, the hub 3 is configuredsuch that the inner race 21 is sandwiched from both side of the axialdirection between the axial outer surface of the staking portion 24 anda step surface 25 facing the inside of the axial direction and existingin the axial outer end portion of the fitting cylinder portion 23 whilethe inner race 21 is externally fitted to the fitting cylinder portion23 of the hub body 22 and the inner race 21 and the hub body 22 arecoupled and fixed to each other. In an example, the hub body 22 includesthe staking portion 24 (the staking portion 24 for holding the innerrace 21) with respect to the inner race 21. The cylinder portion 23 ofthe hub body 22 includes a peripheral wall of which a thickness of atleast a part changes along the axial direction. In the peripheral wallof the cylinder portion 23, one end (first axial end) of the inner race12 in the axial direction is disposed at a first portion (thick part)having a relatively large wall thickness and the other end (second axialend) of the inner race 21 in the axial direction is disposed at a secondportion (thin part) having a relatively small wall thickness. The secondportion of the peripheral wall of the hub body 22 is provided with thestaking portion 24 having a bend extending in the circumferentialdirection and covering the axial end portion (second axial end) of theinner race 21. The staking portion 24 includes a holding portion(staking flange (swage flange, crimp flange), ring edge) 24 a whichextends in the radial direction and the circumferential direction andhas a circular shape as a whole and a curved portion (bent portion,connection portion) 24 b which connects the radial inner end portion ofthe holding portion 24 a and the axial inner end portion of the cylinderportion 23 (FIG. 10 ).

In this embodiment, a plurality of concave portions (engagement concaveportions, concave grooves, recesses, engagement recesses, key grooves)26 provided in the inner race 21 respectively engage with a plurality ofconvex portions (engagement convex portions, protrusions, keys) 27provided in the hub body 22 so that the relative rotation (creep)between the inner race 21 and the hub body 22 is prevented. Theengagement concave portions 26 are formed at a plurality of positions(in the example shown in the drawings, four positions) in thecircumferential direction of the inner race 21 so as to open to theinner peripheral surface of the axial inner end portion and the axialinner end surface 34 of the inner race 21. In other words, theengagement concave portion 26 opens inward in the radial direction andoutward in the axial direction. The engagement convex portion 27 isformed at a plurality of positions in the circumferential direction ofthe axial inner end portion of the fitting cylinder portion 23 of thehub body 22 to protrude outward in the radial direction. For example, aswill be described later, the engagement convex portion 27 can be formedby subjecting an outer peripheral surface of a cylindrical portion 28constituting a hub body 22 z before forming the staking portion 24 to aprotruding process (local shaving process). As shown in FIG. 10 , thestaking portion 24 is formed by plastically deforming the cylindricalportion 28 outward in the radial direction. The phase in thecircumferential direction of the axial outer surface of the stakingportion 24 coincides with that of the engagement convex portion 27. Thephase in the circumferential direction of the concave portion 26 of theinner race 21 coincides with that of the engagement convex portion 27. Aconcave groove 29 which extends outward in the radial direction and isrecessed inward in the axial direction is formed over the radialdirection from a portion adjacent to the outside of the engagementconvex portion 27 in the radial direction.

In other words, the hub body 22 has a shaft shape along a predeterminedaxial direction. The inner race 21 includes a hole 120 into which thehub body 22 is inserted and the concave portion 26 which is provided ina part of the circumferential direction in the wall surface (innersurface, inner peripheral surface) facing the hole 120. The hub body 22includes the convex portion 27 which is provided in a part of the outersurface 23 a in the circumferential direction and engages with theconcave portion 26 of the inner race 21 and the groove (processedgroove, processing mark) 29 which is provided in the outer surface 23 aand extends from the convex portion 27 toward the front end of thestaking portion 24. One end (first end) of the groove 29 in theextension direction is located at one end of the convex portion 27 or inthe vicinity thereof in the hub body 22. The other end (second end) ofthe groove 29 in the extension direction is disposed at a positioncloser to the front end of the staking portion 24 than the convexportion 27. In an example, the extension direction of the groove 29 isparallel to the center axis of the hub body 22. The convex portion 27and the groove 29 are linearly arranged side by side on one line alongthe extension direction of the groove 29. In an example, the first endand the second end of the groove 29 may have different step shapes inthe extension direction. The groove 29 is provided in both the holdingportion 24 a and the curved portion 24 b of the staking portion 24. Inanother example, the groove 29 is provided in the curved portion 24 b ofthe staking portion 24. In another example, the groove 29 is notprovided in the staking portion 24. The groove 29 provided in thestaking portion 24 can be advantageous in preventing the staking portion24 from being broken or cracked in forging (plastic deforming, heading,press forming, bending) for forming the staking portion 24.

The concave portion 26 of the inner race 21 includes a bottom surface(first surface) 126 which intersects (for example, perpendicular to) theaxial direction of the hub body 22 (FIG. 7 ). The convex portion 27 ofthe hub body 22 includes a facing surface (second surface) 127 which isparallel to the first surface 126 of the concave portion 26. The firstsurface 126 and the second surface 127 are in close contact with eachother in the axial direction. The number of the concave portions 26arranged in the circumferential direction can be, for example, 1, 2, 3,4, 5, 6, 7, 8, 9, 10, or more. The number of the convex portions 27arranged in the circumferential direction can be, for example, 1, 2, 3,4, 5, 6, 7, 8, 9, 10, or more. The inner race 21 includes a plurality ofrecesses which are arranged as the concave portions 26 to be away fromeach other. For example, the plurality of recesses include a firstrecess 26A and a second recess 26B which are adjacent to each other(FIG. 9 ). In an example, the distance between the first recess 26A andthe second recess 26B (the peripheral surface length between twoadjacent recesses in the circumferential direction (hereinafter,peripheral surface length)) is twice or more the horizontal width (thewidth (hereinafter, recess width) of the recess in the circumferentialdirection) of the first recess 26A (or the second recess 26B). Forexample, the recess width can be set to ½, ⅓, ¼, ⅕, ⅙, 1/7, ⅛, 1/9,1/10, or less of the peripheral surface length. An area provided withthe concave portion 26 on the inner surface of the inner race 26 is apartial area. For example, the circumferential length of the areaprovided with the concave portion 26 on the inner surface of the innerrace 26 can be 30%, 25%, 20%, 15%, 10%, or 5% or less of the entirecircumferential length.

The hub (staking assembly) 3 and the hub unit bearing 1 described abovecan be manufactured as below. First, the inner race 21 including theinner race track 11 b on the inside of the axial direction and theplurality of engagement concave portions 26 is obtained by subjecting ametal material to necessary processing such as forging or grinding. Forexample, the inner race 21 can be obtained by forging a metal materialto form the rough shape of the inner race 21 and then performing afinishing process such as grinding on the outer peripheral surface toform the inner race track 11 b on the inside of the axial direction. Theengagement concave portion 26 can be formed at the same time when therough shape of the inner race 21 is formed by forging the metalmaterial. Alternatively, the engagement concave portion 26 can be formedby cutting after forming the rough shape of the inner race 21. As willbe described later, the convex portion 27 engaging with the concaveportion 26 is disposed in the concave portion 26 along with theformation of the convex portion 27. In this procedure, for example, thevolume of the convex portion 27 disposed in the concave portion 26gradually increases. This engagement technique has advantages ofeliminating the need for high dimensional accuracy for the concaveportion 26. For example, in the formation of the concave portion 26,cutting can be avoided and forging with dies can be easily applied.

Further, the hub body 22 z before forming the staking portion 24 shownin FIG. 3 is obtained by performing necessary processing such as forgingor grinding on a metal material. That is, the hub body 22 z includes theinner race track 11 a which is on the outside of the axial direction,the rotational flange 12, the fitting cylinder portion 23 and the stepsurface 25, and the cylindrical portion 28 extending inward in the axialdirection from the axial inner end portion of the fitting cylinderportion 23. For example, the outer peripheral surface of the fittingcylinder portion 23 and the outer peripheral surface of the cylindricalportion 28 exist on the same cylindrical surface. The hub body 22 z canbe obtained by forging a metal material to form the rough shape of thehub body 22 z and performing a finishing process such as grinding on theouter peripheral surface.

Next, the hub body 22 z is supported on a support base (not shown) withthe axial outer end portion facing downward and the axial inner endportion facing upward. Then, the rolling element 4 a of the outer row inthe axial direction is disposed around the inner race track 11 a on theoutside of the axial direction in the hub body 22 z to be held by thecage 20 a on the outside of the axial direction. Further, the outer race2 is disposed around the axially intermediate portion of the hub body 22z. Additionally, the outer race 2, the rolling elements 4 a and 4 b, andthe cages 20 a and 20 b are omitted in FIGS. 3 to 10 .

Next, the rolling element 4 b of the inner row in the axial direction isdisposed around the inner race track 11 b on the inside of the axialdirection in the inner race 21 to be held by the cage 20 b on the insideof the axial direction. Then, as shown in FIG. 3 , the axial outer endportion of the inner race 21 is externally fitted (lightly press-fitted)to the axial inner end portion of the cylindrical portion 28 of the hubbody 22 z. At this time, the engagement concave portion 26 of the innerrace 21 and a protrusion portion (blade) 33 of the pressing punch 30disposed above the support base to be displaced in the verticaldirection are set such that the phases in the circumferential directioncoincide with each other.

Next, as shown in FIGS. 3 and 4 , the pressing punch 30 is lowered sothat a pressing surface 31 provided in the pressing punch 30 comes intocontact with the axial inner end surface (axial end surface) 34 of theinner race 21. The protrusion portion (blade) 33 of the pressing punch30 is aligned to the engagement concave portion 26 of the inner race 21in the circumferential direction. The pressing punch 30 includes aconcave portion 32 which opens to the center portion of the lowersurface (front end surface) and has a circular shape when viewed frombelow and includes the pressing surface 31 which is provided around theconcave portion 32 in the lower surface. Further, the pressing punch 30includes the protrusion portion 33 which is provided at a plurality ofpositions (for example, four positions) in the circumferential directionof the inner peripheral surface of the concave portion 32 to protrudeinward in the radial direction. In an example, the protrusion portion 33is formed in the inner peripheral surface of the concave portion 32 overthe axial direction and the lower end portion (front end portion)protrudes downward in relation to the pressing surface 31. Further, theprotrusion portion 33 includes a blade on the inner peripheral edge ofthe lower end surface and both side edges in the circumferentialdirection for performing a protruding process (local shaving process) onthe outer peripheral surface of the cylindrical portion 28 as describedlater.

As shown in FIG. 5 , the lower end portion of the protrusion portion 33is disposed inside the engagement concave portion 26 while the pressingsurface 31 of the pressing punch 30 comes into contact with the axialinner end surface 34 of the inner race 21. Further, the lower endsurface of the protrusion portion 33 faces the bottom surface (thesurface facing the inside of the axial direction) of the engagementconcave portion 26 with a gap therebetween. In other words, when thephases in the circumferential direction (the circumferential positions)between the protrusion portion 33 of the pressing punch 30 and theengagement concave portion 26 of the inner race 21 coincide with eachother, the pressing surface 31 of the pressing punch 30 comes intocontact with the axial inner end surface 34 of the inner race 21. Incontrast, when the phases in the circumferential direction between theprotrusion portion 33 of the pressing punch 30 and the engagementconcave portion 26 of the inner race 21 are displaced, the lower endsurface of the protrusion portion 33 contacts the axial inner endsurface 34 of the inner race 21 and a gap is formed between the pressingsurface 31 and the axial inner end surface 34 of the inner race 21.Thus, it is possible to determine whether or not the phases in thecircumferential direction between the protrusion portion 33 of thepressing punch 30 and the engagement concave portion 26 of the innerrace 21 coincide with each other by determining whether or not thepressing surface 31 of the pressing punch 30 is in contact with theaxial inner end surface 34 of the inner race 21 with naked eyes or bydiagnosing images photographed by a camera. Alternatively, specifically,for example, as will be described later, it may be determined whether ornot the phases in the circumferential direction between the protrusionportion 33 of the pressing punch 30 and the engagement concave portion26 of the inner race 21 coincide with each other depending on the loadapplied to the pressing punch 30 when press-fitting the inner race 21into the fitting cylinder portion 23 of the hub body 22 z and/or formingthe engagement convex portion 27 by a protruding process (local shavingprocess). In another example, the phases (circumferential positions) ofthe concave portion 26 and the protrusion portion 33 may be aligned byrelatively rotating one of the pressing punch 30 and the inner race 21(the hub body 22 z) during press-fitting.

Additionally, the pressing punch 30 including the protrusion portion 33can be integrally formed as a whole and the protrusion portion 33 can beprovided by supporting and fixing a separate member to the innerperipheral surface of the concave portion 32 provided in the bodyportion. If the protrusion portion 33 is provided by supporting andfixing the separate member to the body portion, it is possible to easilyseparate the separate member and polish or replace the separate memberwhen the blade provided in both side edges in the circumferentialdirection and the inner peripheral edge of the lower end surface of theprotrusion portion 33 is worn out. When the blade is a right-angledblade, surface grinding can be easily applied to polishing. Bypolishing, the corners of the blade can be edged. Alternatively, theblade of the protrusion portion 33 can be replaced with another bladehaving an edge if necessary. At least one of the shape and the materialof the protrusion portion (blade) 33 is set in response to the physicalcharacteristics (material and heat treatment) of the hub body 22 z. Forexample, an optimum blade can be attached to the protrusion portion 33in response to the physical characteristics of the hub body 22 z.

Further, when a positioning convex portion protruding downward is formedin the lower surface of the pressing punch 30 separately from theprotrusion portion 33, a positioning concave portion protruding outwardin the axial direction is formed in the axial inner end surface 34 ofthe inner race 21 separately from the engagement concave portion 26, andthe positioning convex portion and the positioning concave portionengage with each other while the pressing surface 31 of the pressingpunch 30 is in contact with the axial inner end surface 34 of the innerrace 21, the phases in the circumferential direction between the innerrace 21 and the pressing punch 30 can be allowed to coincide with eachother. In this case, it is preferable to regulate the dimension of eachportion so that a gap exists between the lower end surface of theprotrusion portion 33 and the bottom surface of the engagement concaveportion 26 when the front end surface (the lower end surface) of thepositioning convex portion comes into contact with the bottom surface(the surface facing the inside of the axial direction) of thepositioning concave portion while the pressing surface 31 of thepressing punch 30 is in contact with the axial inner end surface 34 ofthe inner race 21.

Next, as shown in FIGS. 4 to 6 , a press-fitting step and an engagingstep are performed at the same time. In the press-fitting step, thepressing punch 30 is further lowered so that the inner race 21 ispress-fitted into the fitting cylinder portion 23 of the hub body 22 z.The inner race 21 and the hub body 22 z are combined (assembled, fitted)in the axial direction. In the engaging step, the engagement convexportion 27 is allowed to engage with the engagement concave portion 26while forming the engagement convex portion 27 by forming a concavegroove 29 z. In the initial stage of the axial relative movement betweenthe pressing punch 30 and the hub body 22 z, (a) the pressing surface 31of the pressing punch 30 comes into contact with the inner race 21, (b)at least a part of the protrusion portion (blade) 33 of the pressingpunch 30 is disposed inside the engagement concave portion 26 of theinner race 21, and (c) an axial gap is provided between the protrusionportion (blade) 33 and the inner surface of the engagement concaveportion 26 (FIG. 5 ). In accordance with the axial relative movementbetween the pressing punch 30 and the hub body 22 z, the axial relativemovement of the pressing punch (auxiliary member) 30 and the hub body 22z is performed. That is, the axial inner end surface 34 of the innerrace 21 is pressed outward (downward) in the axial direction by thepressing surface 31 until the outer end surface of the inner race 21 inthe axial direction collides with the step surface 25. Accordingly, theinner race 21 is press-fitted into the fitting cylinder portion 23 ofthe hub body 22 z. At the same time, a plurality of positions in thecircumferential direction of the radial outer portion of the cylindricalportion 28 of the hub body 22 z are pressed outward in the axialdirection by the lower end surface of the protrusion portion 33 to beplastically deformed (so that a protruding process (local shavingprocess) is performed). As shown in FIG. 7 , an extra thicknessgenerated as a result of forming the concave groove 29 z is crushedbetween the lower end surface of the protrusion portion 33 and thebottom surface of the engagement concave portion 26 and the engagementconvex portion 27 protruding outward in the radial direction is formedat a plurality of positions in the circumferential direction of theaxial inner end portion of the fitting cylinder portion 23. Further, theengagement convex portion 27 is disposed inside the engagement concaveportion 26 of the inner race 21 and the engagement convex portion 27engages with the engagement concave portion 26. That is, a part of thehub body 22 z deformed (shaved, partially shaved) by the protrusionportion (blade) 33 of the pressing punch 30 in the axial relativemovement between the pressing punch 30 and the hub body 22 z is disposedinside the engagement concave portion 26 of the inner race 21.Accordingly, the creep (displacement) between the inner race 21 and thehub body 22 z is prevented. In an example, as shown in FIG. 7 , a gapexists between the pressing surface 31 and the axial inner end surface34 of the inner race 21 in a completed state of the press-fitting stepand the engaging step in which the pressing punch 30 is lowered to abottom dead center. However, the pressing surface 31 and the axial innerend surface 34 of the inner race 21 can be brought into contact witheach other in the completed state of the press-fitting step and theengaging step. Additionally, a groove (processed groove, processingmark) 29 z opening to the axial inner end surface is formed in a portionin which the phase in the circumferential direction in the outerperipheral surface of the cylindrical portion 28 coincides with that ofthe engagement convex portion 27 as the engagement convex portion 27 isformed by a protruding process (local shaving process). In addition, theinner race 21 can be press-fitted into the hub body 22 z with arelatively light force (light press-fitting). This is because thedisplacement between the inner race 21 and the hub body 22 is suppressedby the engagement convex portion 27. For example, the press-fittingmargin can be set to a value close to zero.

Next, as shown in FIGS. 6 to 8 , the pressing punch 30 is raised(retracted). Then, it is confirmed whether or not the engagement concaveportion 26 of the inner race 21 engages with the engagement convexportion 27 of the hub body 22 z with naked eyes or diagnosing imagesphotographed by a camera.

When the engagement concave portion 26 and the engagement convex portion27 engage with each other, as shown in FIG. 10 , the staking portion 24is formed by plastically deforming the cylindrical portion 28 of the hubbody 22 z outward in the radial direction. In this way, the hub unitbearing 1 of this example is obtained by processing the hub body 22 zinto the hub body 22 and coupling and fixing the inner race 21 and thehub body 22 to each other.

Additionally, various methods known from the past can be used for themethod of processing the cylindrical portion 28 into the staking portion24. For example, a stamp having a center axis inclined with respect tothe center axis of the hub body 22 z supported by the support base ispressed against the cylindrical portion 28. In this state, the stakingportion 24 can be formed by swaging in which the stamp is swung aroundthe center axis of the hub body 22 z like a locus of the center axis dueto precession. Alternatively, the staking portion 24 may be formed byflat-pressing in which a mold is pressed in the axial direction.

Further, the process of manufacturing the hub unit bearing 1 can bechanged in order as appropriate or changed to be carried outsimultaneously or separately as long as there is no contradiction. Thatis, for example, when the inner race 21 is press-fitted into the fittingcylinder portion 23 of the hub body 22 z and a plurality of positions inthe circumferential direction of the radial outer portion of thecylindrical portion 28 of the hub body 22 z is subjected to a protrudingprocess (local shaving process), the engagement convex portion 27 canengage with the engagement concave portion 26 of the inner race 21 whileforming the engagement convex portion 27.

In the hub unit bearing 1 of this embodiment, since the engagementconcave portion 26 of the inner race 21 engages with the engagementconvex portion 27 of the hub body 22, it is possible to reliably preventcreep from occurring between the inner race 21 and the hub body 22.

Further, in this embodiment, it is possible to satisfactorily ensure thebearing performance of the hub unit bearing 1. That is, when the axialinner end surface of the inner race is strongly pressed by the stakingportion in order to prevent the creep between the hub body and the innerrace, the inner race is elastically deformed so that the inner racetrack on the inside of the axial direction expands. In contrast, in thisembodiment, since the creep between the inner race 21 and the hub body22 is prevented due to the engagement between the engagement concaveportion 26 of the inner race 21 and the engagement convex portion 27 ofthe hub body 22, there is no need to excessively increase a force inwhich the axial inner end surface 34 of the inner race 21 is held downby the staking portion 24 to prevent the occurrence of creep. That is,the staking portion 24 may suffice to hold the axial inner end surface34 of the inner race 21 with a force sufficient to prevent the innerrace 21 from being displaced inward in the axial direction. Therefore,the elastic deformation amount of the inner race 21 can be suppressed tobe small and the bearing performance can be satisfactorily ensured.Further, since there is no need to excessively increase a force in whichthe staking portion 24 holds down the axial inner end surface 34 of theinner race 21 and the processing load when forming the staking portion24 can be suppressed to be small, a processing machine can be decreasedin size.

Further, in this example, the engagement convex portion 27 engages withthe engagement concave portion 26 opening to the axial inner end surface34 of the inner race 21 and the inner peripheral surface of the axialinner end portion. Thus, it is possible to easily confirm whether or notthe engagement concave portion 26 engages with the engagement convexportion 27 in the state before forming the staking portion 24, that is,whether or not creep between the inner race 21 and the hub body 22 z isreliably prevented with naked eyes or diagnosing images photographed bya camera. Therefore, it is possible to suppress the occurrence ofdefective products and improve the yield.

Additionally, in this example, each of the engagement concave portion 26and the engagement convex portion 27 is formed at four positions, butthe number of the engagement concave portions and the engagement convexportions is not particularly limited and can be one to three or five ormore as long as the creep between the inner race and the hub body can beprevented. Further, the shapes and dimensions of the engagement concaveportion 26 and the engagement convex portion 27 are not particularlylimited as long as the creep between the inner race and the hub body canbe prevented, the engagement convex portion can be formed by aprotruding process (local shaving process), and the strength andrigidity of the inner race and the hub body can be sufficiently ensured.

The rolling elements 4 a and 4 b are not limited to tapered rollers.Balls can also be used as the rolling elements 4 a and 4 b. Further, inthe present invention, the hub body 9 a is not limited to a hub unitbearing for a solid driven wheel, but can be also applied to a hub unitbearing for a drive wheel having an engagement hole such as a splinehole for engaging a drive shaft enabling torque transmission in thecenter of the hub body.

FIG. 11(a) to FIG. 11(d) are schematic horizontal cross-sectional viewshowing the engagement concave portion 26 of the inner race 21 and theengagement convex portion 27 of the hub body 22. In the example of FIG.11(a), the convex portion 27 contacts the wall surface of the concaveportion 26 in the radial direction and the circumferential direction. Inthe example of FIG. 11(b), the convex portion 27 contacts the wallsurface of the concave portion 26 in the circumferential direction.There is a gap between the wall surface of the concave portion 26 andthe convex portion 27 in the radial direction. In the example of FIG.11(c), the convex portion 27 contacts the wall surface of the concaveportion 26 in the radial direction. There is a gap between the wallsurface of the concave portion 26 and the convex portion 27 in thecircumferential direction. In the example of FIG. 11(d), the convexportion 27 is formed such that a gap exists between the wall surface ofthe concave portion 26 and the convex portion 27 in the radial directionand the circumferential direction. When the contact area of the wallsurface of the concave portion 26 and the convex portion is large, thedisplacement between the inner race 21 and the hub body 22 is reliablyprevented. When the contact area of the wall surface of the concaveportion 26 and the convex portion is small, an excessive stress isprevented. Additionally, the convex portion 27 formed by a protrudingprocess (local shaving process) can have a higher hardness than otherportions of the hub body 22.

FIG. 12 is a partial schematic view of a vehicle 200 including a hubunit bearing (bearing unit) 151. The present invention can be applied toany one of a hub unit bearing for a drive wheel and a hub unit bearingfor a driven wheel. In FIG. 12 , a hub unit bearing 151 is for a drivewheel and includes an outer race 152, a hub 153, and a plurality ofrolling elements 156. The outer race 152 is fixed to a knuckle 201 of asuspension device by a bolt and the like. A vehicle wheel (and a brakingrotation body 22) 202 is fixed to a flange (rotational flange) 153Aprovided in the hub 153 using a bolt and the like. Further, the vehicle200 can have the above-described support structure for the hub unitbearing 151 for a driven wheel.

The present invention is not limited to the hub of the hub unit bearingand can be also applied to other staking assemblies (staking units) inwhich a first member and a second member having a hole into which thefirst member is inserted are combined.

REFERENCE SIGNS LIST

-   -   1 Hub unit bearing    -   2 Outer race    -   3 Hub (staking assembly, staking unit)    -   4 a, 4 b Rolling element    -   5 a, 5 b Outer race track    -   6 Stationary flange    -   7 Support hole    -   8 Knuckle    -   9 Passage hole    -   10 Bolt    -   11 a, 11 b Inner race track    -   12 Rotational flange    -   13 Attachment hole    -   14 Braking rotation body    -   15 Stud    -   16 Passage hole    -   17 Wheel    -   18 Passage hole    -   19 Nut    -   20 a, 20 b Cage    -   21 Inner race (second member)    -   22, 22 z Hub body (first member)    -   23 Fitting cylinder portion    -   24 Staking portion    -   25 Step surface    -   26 Engagement concave portion (concave portion)    -   27 Engagement convex portion    -   28 Cylindrical portion    -   29, 29 z Concave groove (groove, processed groove, processing        mark)    -   30 Pressing punch (auxiliary member)    -   31 Pressing surface    -   32 Concave portion    -   33 Protrusion portion (blade)    -   34 Axial inner end surface    -   100 Hub unit bearing    -   101 Outer race    -   102 Hub    -   103 Rolling element    -   104 a, 104 b Outer race track    -   105 Stationary flange    -   106 a, 106 b Inner race track    -   107 Rotational flange    -   108 Hub body    -   109 Inner race    -   110 Fitting cylinder portion    -   111 Step surface    -   112 Staking portion    -   120 Hole    -   126 Bottom surface (first surface)    -   127 Facing surface (second surface)

What is claimed is:
 1. A method of manufacturing a staking assemblycomprising: preparing a first member, a second member including anengagement concave portion and a hole allowing the first member to beinserted thereinto, and an auxiliary member including a blade; combiningthe first member and the second member with each other in an axialdirection; moving the auxiliary member and the first member relativelyin an axial direction so that a part of the first member deformed by theblade of the auxiliary member in the axial relative movement is disposedinside the engagement concave portion of the second member; and forminga staking portion with respect to the second member in the first member.2. The method of manufacturing a staking assembly according to claim 1,wherein the first member is combined with the second member in the axialdirection in accordance with the relative movement between the auxiliarymember and the first member.
 3. The method of manufacturing a stakingassembly according to claim 1, wherein the auxiliary member includes apressing surface, and wherein in the relative movement between theauxiliary member and the first member, (a) the pressing surface of theauxiliary member comes into contact with the second member, (b) at leasta part of the blade of the auxiliary member is disposed inside theengagement concave portion of the second member, and (c) an axial gap isprovided between the blade and an inner surface of the engagementconcave portion.
 4. The method of manufacturing a staking assemblyaccording to claim 1, wherein the blade is positioned to a position ofthe engagement concave portion of the second member in a circumferentialdirection before the relative movement between the auxiliary member andthe first member.
 5. The method of manufacturing a staking assemblyaccording to claim 1, wherein at least one of a shape and a material ofthe blade is set in response to physical characteristics of the firstmember.
 6. The method of manufacturing a staking assembly according toclaim 1, wherein the first member and the second member are combinedwith each other by light press-fitting.
 7. A method of manufacturing astaking assembly comprising: preparing a first member, a second memberincluding a concave portion and a hole allowing the first member to beinserted thereinto, and an auxiliary member; moving the auxiliary memberand the first member relatively in an axial direction and including (a)combining the first member with the second member in the axial directionin accordance with the axial relative movement and (b) forming a convexportion engaging with the concave portion in accordance with the axialrelative movement in the first member by the auxiliary member; andforming a staking portion with respect to the second member in the firstmember.
 8. A staking assembly comprising: a first member; and a secondmember including a hole allowing the first member to be insertedthereinto and combined with the first member, wherein the second memberincludes a concave portion, and wherein the first member includes astaking portion with respect to the second member, a convex portionprovided in an outer surface of the first member and engaging with theconcave portion of the second member, and a groove provided in the outersurface of the first member and extending from the convex portion towarda front end of the staking portion.
 9. A staking assembly comprising: afirst member; and a second member including a hole allowing the firstmember to be inserted thereinto and combined with the first member,wherein the second member includes a concave portion, wherein the firstmember includes a staking portion with respect to the second member anda convex portion provided in an outer surface of the first member andengaging with the concave portion of the second member, wherein theconcave portion of the second member includes a first surfaceintersecting an axial direction of the first member, wherein the convexportion of the first member includes a second surface parallel to thefirst surface of the concave portion, and wherein the first surface andthe second surface are in close contact with each other in the axialdirection.
 10. The staking assembly according to claim 8, wherein thesecond member includes a plurality of recesses arranged as the concaveportions to be separated from each other, wherein the plurality ofrecesses include a first recess and a second recess which are close toeach other, and wherein a distance between the first recess and thesecond recess is twice or more a horizontal width of the first recess orthe second recess.
 11. A hub unit bearing comprising: an outer raceincluding an outer race track; a hub including an inner race track; anda plurality of rolling elements arranged between the outer race trackand the inner race track, wherein the hub includes a hub body includingan outer surface and an inner race disposed on the outer surface of thehub body and held by the hub body, wherein the inner race includes aconcave portion, and wherein the hub body includes a staking portionwith respect to the inner race, a convex portion provided in the outersurface of the hub body and engaging with the concave portion of theinner race, and a groove provided in the outer surface of the hub bodyand extending from the convex portion toward a front end of the stakingportion.
 12. A hub unit bearing comprising: an outer race including adouble row of outer race tracks provided in an inner peripheral surface;a hub including a double row of inner race tracks provided in an outerperipheral surface; and a plurality of rolling elements which arearranged for each row between the double row of the outer race tracksand the double row of the inner race tracks in a rolling manner, whereinthe hub includes an inner race and a hub body, wherein the inner raceincludes an inner race track on the inside of an axial direction in thedouble row of the inner race tracks on the outer peripheral surface,wherein the hub body includes an inner race track which is formed in anouter peripheral surface of an axially intermediate portion directly orthrough another member and is located on the outside of the axialdirection in the double row of the inner race tracks, a fitting cylinderportion which exists on the inside of the axial direction in relation tothe inner race track on the outside of the axial direction and to whichthe inner race is externally fitted, and a staking portion which is bentoutward in a radial direction from an axial inner end portion of thefitting cylinder portion and holds down an axial inner end surface ofthe inner race, wherein the inner race includes an engagement concaveportion provided at one or a plurality of positions in a circumferentialdirection to open to the axial inner end surface and the innerperipheral surface, and wherein the hub body includes an engagementconvex portion provided at one or a plurality of positions in thecircumferential direction to engage with the engagement concave portion.13. The hub unit bearing according to claim 12, wherein the hub bodyfurther includes a concave groove which is recessed inward in the axialdirection and extends outward in the radial direction from a portionwhich is close to the outside of the engagement convex portion in theradial direction and in which a phase in the circumferential directioncoincides with that of the engagement convex portion in an axial outersurface of the staking portion.
 14. A method of manufacturing the hubunit bearing according to claim 13 comprising: press-fitting the innerrace into the fitting cylinder portion of the hub body before formingthe staking portion; allowing the engagement convex portion to engagewith the engagement concave portion of the inner race while forming theengagement convex portion and the concave groove by pressing one or aplurality of positions in the circumferential direction of a radialouter portion of a cylindrical portion, extending inward in an axialdirection from the fitting cylinder portion of the hub body beforeforming the staking portion, outward in the axial direction to beplastically deformed; and coupling and fixing the inner race and the hubbody by plastically deforming the cylindrical portion outward in theradial direction to form the staking portion.
 15. The method ofmanufacturing a hub unit bearing according to claim 14, wherein thepress-fitting and the engaging are performed at the same time.
 16. Themethod of manufacturing a hub unit bearing according to claim 15,wherein the inner race is press-fitted into the fitting cylinder portionof the hub body before forming the staking portion by pressing the innerrace, externally fitted to an axial inner end portion of the hub bodybefore forming the staking portion, outward in the axial direction by aportion deviating from a protrusion portion in a pressing punchincluding the protrusion portion protruding inward in the radialdirection at one or a plurality of positions of an inner peripheralsurface in the circumferential direction and the engagement convexportion is allowed to engage with the engagement concave portion of theinner race while forming the engagement convex portion by pressing oneor a plurality of positions in the circumferential direction of theradial outer portion of the cylindrical portion outward in the axialdirection to be plastically deformed by the protrusion portion.
 17. Themethod of manufacturing a hub unit bearing according to claim 5, whereinthe pressing punch includes a pressing surface on a front end surface,and wherein a gap exists between a front end surface of the protrusionportion and a bottom surface of the engagement concave portion while thepressing surface comes into contact with a portion deviating from theengagement concave portion in an axial inner end surface of the innerrace when performing the press-fitting and the engaging at the sametime.
 18. The method of manufacturing a hub unit bearing according toclaim 14, further comprising: confirming whether or not the engagementconvex portion engages with the engagement concave portion after theengaging.
 19. A method of manufacturing a hub unit bearing, wherein thehub unit bearing includes an outer race including an outer race track, ahub including an inner race track, and a plurality of rolling elementsarranged between the outer race track and the inner race track, whereinthe hub includes a hub body including an outer surface and an inner racedisposed on the outer surface of the hub body and held by the hub body,wherein the method comprises: preparing the inner race including anengagement concave portion and an auxiliary member including a blade;combining the hub body and the inner race with each other in an axialdirection; moving the auxiliary member and the hub body relatively inthe axial direction so that a part of the hub body deformed (shaved) bythe blade in the axial relative movement is disposed inside theengagement concave portion of the inner race; and forming a stakingportion with respect to the inner race in the hub body.
 20. Anautomobile comprising: the staking assembly according to claim
 8. 21. Amethod of manufacturing an automobile including a hub unit bearing,wherein the hub unit bearing is manufactured by the method ofmanufacturing a hub unit bearing according to claim 14.